Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B13/00—Gearwork
  • G04B13/02—Wheels; Pinions; Spindles; Pivots
• • G—PHYSICS
  • G04—HOROLOGY
  • G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
  • G04D3/00—Watchmakers' or watch-repairers' machines or tools for working materials
  • G04D3/0074—Watchmakers' or watch-repairers' machines or tools for working materials for treatment of the material, e.g. surface treatment
  • G04D3/0087—Watchmakers' or watch-repairers' machines or tools for working materials for treatment of the material, e.g. surface treatment for components of the escapement mechanism, e.g. lever escapement, escape wheel
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D1/00—Electroforming
  • C25D1/003—3D structures, e.g. superposed patterned layers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/0035—Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/16—Coating processes; Apparatus therefor
  • G03F7/164—Coating processes; Apparatus therefor using electric, electrostatic or magnetic means; powder coating
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B15/00—Escapements
  • G04B15/14—Component parts or constructional details, e.g. construction of the lever or the escape wheel

Definitions

• the present invention relates to a method for manufacturing a multi-level metallic structure using LIGA technology.
• the invention also relates to such a metallic structure, in particular horological components, obtained by this process.
• Patent document WO2010 / 020515A1 describes the manufacture of a part on several levels by producing a complete photoresist mold corresponding to the final part to be obtained before the step of galvanically depositing the metal of the part in the mold. Only multi-level rooms whose level projections are included in one another are achievable by this method. This process also has certain drawbacks. In particular, galvanic growth starts everywhere and the growth fronts meet and cause unwanted inclusions. Also known from patent document EP2405301A1 is a photoresist mold comprising at least two levels, the levels formed in the substrate comprising only vertical and smooth sides. The disadvantage of such a method is that it requires a large overgrowth to fill the second level, which can also cause undesirable inclusions in the corners of the mold.
• the present invention aims to remedy the aforementioned drawbacks as well as others by providing a method for manufacturing multi-level metallic watch components using LIGA technology in which a conductive layer is associated with a layer of resin for each level to allow reliable galvanic growth in the case of multilevel components having a medium to strong slenderness of the second level.
• the present invention also aims to provide such a method which makes it possible to avoid metallization of the blanks during the deposition of the electrically conductive layer or layers.
• the invention relates to a process for manufacturing a timepiece component comprising the following steps:
• a) provide the substrate, deposit a first electrically conductive layer there, and apply a first layer of photosensitive resin; b) irradiating the first layer of resin through a mask defining a first level of the component and dissolving the non-irradiated zones of the layer of photosensitive resin so as to cause the first electrically conductive layer to appear;
• step c applying a second layer of photosensitive resin covering the structure resulting from step c); e) irradiating the second layer of resin through a mask defining a second level of the component and dissolving the non-irradiated zones of the second layer of photosensitive resin to form a mold comprising a first and a second level and making the first layer appear in places and the second electrically conductive layer;
• This process therefore allows the production of multi-level parts.
• the second electrically conductive layer is deposited through a mask mask
• the second electrically conductive layer is applied by global deposition on all exposed surfaces (including sides) then removed entirely except on the upper surface of the first resin layer, where it has been protected by means of a savings deposited by buffering;
• the second electrically conductive layer is deposited by printing an ink or a conductive resin;
• Said first layer and said second electrically conductive layer are of the Au, Ti, Pt, Ag, Cr, Pd type or a stack of at least two of these materials;
• the substrate is made of silicon
• the first conductive layer has a thickness between 50nm and 500nm;
• the second conductive layer has a thickness between 50nm and 500nm;
• the invention relates to a timepiece component, obtained according to a process according to the invention, such as an anchor or an escapement wheel for example.
• FIGS 1 to 11 illustrate the process steps of an embodiment of the invention for the production of a timepiece component. Detailed description of a preferred embodiment
• the substrate 1 used in step a) of the method according to the invention is, for example, formed by a silicon substrate.
• a first conductive layer 2 is deposited, that is to say a layer capable of starting a metallic deposit by galvanic means .
• the first conductive layer 2 is of the Au, Ti, Pt, Ag, Cr or Pd type (FIG. 1), or a stack of at least two of these materials, and has a thickness of between 50 nm and 500 nm.
• the first conductive layer 2 can be formed of an under layer of chromium or titanium covered with a layer of gold or copper.
• the photosensitive resin 3 used in this process is preferably a negative type resin based on octofunctional epoxy available from Microchem under the reference SU-8 designed to polymerize under the action of UV radiation.
• the resin is in the form of a dry film, the resin is then applied by rolling on the substrate 1.
• the photosensitive resin could be a positive photoresist which is designed to decompose under the action of UV radiation. It will be understood that the present invention is not limited to a few particular types of photosensitive resin. Those skilled in the art will be able to choose a photosensitive resin suitable for their needs from all the known resins which are suitable for UV photolithography.
• the first resin layer 3 is deposited on the substrate 1 by any suitable means, by centrifugal coating, with a spinner, or even by spraying to the desired thickness.
• the resin thickness is between 10 ⁇ m and 1000 ⁇ m, and preferably between 30 ⁇ m and 300 mhi.
• the first layer of resin 3 will be deposited in one or more times.
• the first layer of resin 3 is then typically heated to between 90 and 120 ° C for a period of time depending on the thickness deposited to remove the solvent (pre-bake step). This heating dries and hardens the resin.
• the first layer of resin 3 undergoes a thickening step during which the resin is machined.
• the resin is again heated so as to "stretch" its surface.
• the next step b) illustrated in FIG. 2 consists in irradiating the first resin layer 3 by means of UV radiation through a mask 4 defining the first level of the component to be formed and thus photopolymerized zones 3a and non- light-cured 3b.
• An annealing step (post-bake step) of the first resin layer 3 may be necessary to complete the photopolymerization induced by UV irradiation. This annealing step is preferably carried out between 90 ° C and 95 ° C.
• the photopolymerized zones 3a become insensitive to a large majority of solvents.
• the non-light-cured areas may subsequently be dissolved by a solvent.
• step c) illustrated in FIG. 4 consists in depositing a second conductive layer 5 on the photopolymerized zones 3a during the previous step.
• This second conductive layer 5 can have the same characteristics as the first conductive layer 2, namely that it is of the Au, Ti, Pt, Ag, Cr, Pd type or a stack of at least two of these materials, and has a thickness between 50nm and 500nm.
• a mask mask is used which is positioned via an optical alignment.
• Such equipment makes it possible to guarantee good alignment of the mask with the geometry of the photopolymerized zones 3a on the substrate and thus guarantee a deposit only on the upper surface of the first conductive layer 2 while avoiding a deposit on the sides of the photopolymerized resin 3a because the mask is kept as close as possible to the substrate 1.
• the second electrically conductive layer is implemented by global deposition on all the exposed surfaces (including sides) then removed entirely except on the upper surface of the first resin layer, where it has been protected against by means of a savings deposited by stamping.
• the next step d) illustrated in FIG. 5 consists in depositing a second layer 6 of photosensitive resin covering the structure resulting from the previous step.
• the same resin is used during this step, and the thickness is greater than that deposited during step a).
• the thickness varies according to the geometry of the component that one wishes to obtain.
• the second resin layer 6 undergoes a thicknessing step during which the resin is mechanically machined. In order to eliminate all machining marks and obtain a perfectly flat surface, the resin is again heated so as to "stretch" its surface.
• step e) illustrated in FIG. 6 consists in irradiating the second layer 6 of resin through a mask 4 "defining a second level of the component and dissolving the non-irradiated zones 6b of the second layer 6 of photosensitive resin.
• a mold is obtained comprising a first and a second level revealing in places the first electrically conductive layer 2 and the second electrically conductive layer 5.
• step f) illustrated in FIG. 8 consists in depositing in the mold, by electroforming or galvanic deposition, a layer 7 of a metal from the first layer 2 and second layer 5 electrically conductive until forming a block reaching preferably a height less than the height of the mold, this allowing better mechanical strength during subsequent machining.
• metal in this context are understood, of course, metal alloys.
• the metal will be chosen from the group comprising nickel, copper, gold or silver, and, as an alloy, gold-copper, nickel-cobalt, nickel-iron, nickel-phosphorus , or nickel-tungsten.
• the multilayer metal structure is entirely made of the same alloy or metal. However, it is also possible to change the metal or alloy during the galvanic deposition step so as to obtain a metallic structure comprising at least two layers of different natures.
• the electroforming conditions in particular the composition of the baths, the geometry of the system, the voltages and current densities, are chosen for each metal or alloy to be electrodeposited according to techniques well known in the art of electroforming.
• the following step g) illustrated in FIG. 9 consists in machining by a mechanical process the metal layer 7 to a thickness predefined by the thickness of the component to be produced.
• step h) illustrated in FIG. 10 consists in carrying out mechanical machining operations such as chamfers on the edges of the visible face of the component for example, or also threads or countersinks in the component.
• the operations will obviously depend on the geometry of the final component that one wishes to obtain.
• Step i) consists in releasing the component by eliminating, by a succession of etching steps, wet or dry, the substrate, the conductive layers or the resin layers, operations familiar to those skilled in the art.
• the first conductive layer 2 and the substrate 1 are removed by means of wet etching, which makes it possible to release the component from the substrate 1 without damaging it.
• the silicon substrate can be etched with a solution based on potassium hydroxide (KOH).
• a 2nd sequence is to remove the first layer 3 and the second resin layer 6 by means of O2 plasma prints spaced wet prints of metal interlayers.
• the components obtained can be cleaned, and possibly taken up on a machine tool to carry out machining or an aesthetic termination.
• the parts can be directly used or subjected to various decorative and / or functional treatments, typically physical or chemical deposits.
• a thickness is applied by a machining operation of each layer of resin 3, 6.
• this operation makes it possible to finely control the geometry of the parts on the scale of the substrate 1 (wafer).
• a heat treatment is carried out to overcome the traces of machining.
• the method of the invention finds a particularly advantageous application for the manufacture of components for timepieces, such as springs, anchors, wheels, etc. Thanks to this process, robust components can be obtained which have good reliability in terms of geometries.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Micromachines (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (5)

Family Cites Families (12)

• 2018
  • 2018-08-22 EP EP18190253.7A patent/EP3614205A1/fr not_active Withdrawn
• 2019
  • 2019-08-22 JP JP2021501034A patent/JP6992210B2/ja active Active
  • 2019-08-22 WO PCT/EP2019/072484 patent/WO2020039032A1/fr active Search and Examination
  • 2019-08-22 US US17/252,572 patent/US11181868B2/en active Active
  • 2019-08-22 CN CN201980051250.9A patent/CN112513735A/zh active Pending
  • 2019-08-22 KR KR1020217004620A patent/KR102319945B1/ko active IP Right Grant
  • 2019-08-22 EP EP19756370.3A patent/EP3841433B1/fr active Active

Patent Citations (6)

Non-Patent Citations (1)

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